Light-emitting diode crystal grains are generally formed on a substrate by epitaxial growth method. To separate the crystal grains from the substrate, an auxiliary substrate with an adhesive layer is needed, and the auxiliary substrate is pressed to the crystal grains, and the adhesive layer also fills gaps between the light emitting diode crystal grains. A laser beam can irradiate the substrate to separate the crystal grain from the substrate. However, when using a laser beam to irradiate the substrate, the adhesive layer is easily overheated, and the crystal grains are not easily separated from the adhesive layer.
The above-mentioned disadvantages need to be overcome.